Android:在AsyncTask中传递String参数?

时间:2012-05-22 21:58:48

标签: android rss android-asynctask

我正在实施一个Android应用来加载RSS Feed。它完全正常,直到我决定添加一个新屏幕来显示两个按钮并尝试将String值传递给AsyncTask。这个想法是这样的:屏幕将显示两个按钮供用户选择。一旦用户点击其中一个按钮,它将调用AsyncTask以及字符串值(url)来读取RSS(url),然后rss feed由displayRSS(url)显示。 readRSS(url)将相应地加载RSS提要。

我的代码如下:

import java.util.List;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;

public class RSSProActivity extends Activity {

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.rss);
        startLoadRSS();

    }

    private void startLoadRSS(){
        new RSS_Load().execute();
    }

    //
    private void preReadRSS()
    {
        Toast.makeText(this, "Reading RSS, Please wait.", Toast.LENGTH_LONG).show();
    }

        private StringBuffer readRSS(String url)
        {
            //depends on the inputs, will set the String value accordingly. It should be "url" but using the default value at the moment.

            String urlStr = "http://www.bom.gov.au/fwo/IDZ00059.warnings_vic.xml";
            AndroidSAXFeedParser saxFeedParser = new AndroidSAXFeedParser(urlStr);
            List<RSSItem> parse = saxFeedParser.parse();
            StringBuffer sb = new StringBuffer();
            sb.append(parse.size()+" items found");
            for(RSSItem item:parse){
                sb.append(item.getTitle()+"posted at "+item.getDate());
                sb.append(item.getDescription());
            }
            return sb;
        }

        private void displayRSS()
        {
            StringBuffer sb = readRSS(url);
            TextView textView = new TextView(this);
            textView.setText(sb.toString());
            setContentView(textView);
            Toast.makeText(this, "SUCCESS", Toast.LENGTH_LONG).show();
        }


        //AsyncTask
        public class RSS_Load extends AsyncTask<Void, Void, Void>{
           @Override
           protected void onPreExecute() {
              super.onPreExecute();
              preReadRSS();
           }

           @Override
           protected Void doInBackground(Void... arg0) {
             readRSS();
                       // should be readRSS(url) here
               return null;
           }

           @Override
           protected void onProgressUpdate(Void... values) {
              //super.onProgressUpdate(values);
          //    updateProgressBar(values[0]);

           }

           @Override
           protected void onPostExecute(Void result) {
              super.onPostExecute(result);
           //   dismissProgressBar();
                // should be displayRSS(url) here
            displayRSS();

           }               

 }
}

我正在尝试更改RSS_Load扩展AsyncTask中的值,但它给了我编译错误。所以我更改了受保护的Void doInBackground(String ... url),然后将url传递给readRSS(url),但它也不起作用。我该怎么做到这一点?

提前致谢!

1 个答案:

答案 0 :(得分:4)

...意味着它实际上正在传递该类型的数组。因此,如果您将其更改为:

protected Void doInBackground(String... arg0)

你需要这样做:

@Override
protected Void doInBackground(String... arg0)
{
    readRSS(arg0[0]);
    // should be readRSS(url) here
    return null;
}